In a glass plate breaking machine, a glass plate with a breaking line formed beforehand thereon is placed on an endless belt, a breaking unit is moved along the breaking line on the glass plate in a plane parallel to the surface of the glass plate over the glass plate, while a glass plate receiver is moved below the glass plate in correspondence to the movement of the breaking unit.
In the conventional glass plate breaking machine, the glass plate receiver is moved in correspondence to the movement of the breaking unit below the glass plate and more particularly on the inner side of the endless belt, so that a support plate which supports the endless belt is required to have a large window (opening). As a result, that portion of the endless belt on which the glass plate is placed is difficult to support wholly from below, so that it is supported only at its peripheral portion and as a result the belt would hang at its middle portion. In that case, the movement of the glass plate receiver is difficult to move below the belt. If the receiver is forcedly moved, the glass plate receiver would be caught by the belt to thereby damage same.
The glass plate receiver of the conventional glass plate breaking machine has a fixed step. A cutter blade is pressed against that portion of a glass plate supported by an upper surface, which defines the fixed step, to form an end cutting line (auxiliary cutting line) on the glass plate. The fixed step is then disposed along the breaking line on the glass plate with the end cutting lines formed. A push rod then presses the glass plate against a lower surface, which defines the fixed step, to break the glass plate along its breaking line.
With the glass plate receiver with the upper and lower surfaces provided through the fixed step, as mentioned above, it is only the upper surface surrounded substantially by the lower surface that can support that portion of the glass plate pressed by the cutter blade when the end cutting line is formed. Therefore, the cutter blade must be positioned relative to the upper surface. As a result, the accuracy of relatively positioning the cutter blade must be increased. Since it is the upper surface having a small area surrounded by the lower surface that can support the glass plate, support is unstable.
Such a problem arises not only with glass plates but also with general plate-like members to be broken.
In view of the above problems, the present invention has been made. It is an object of the present invention to provide a glass plate breaking machine which minimizes hanging down of the endless belt, and is capable of supporting that portion of a glass plate, on which the breaking unit acts, with the glass plate receiver as desired without damaging the plate.
It is another object of the present invention to provide a glass plate breaking machine which provides a widened support surface which supports that portion of a glass plate pressed by the cutter blade, ensuring support of the glass plate in a stabilized manner without increasing greatly the accuracy of relatively positioning the cutter blade and a support surface which supports that portion of the glass plate pressed by the cutter blade.